Sound Pollution
Noise, by definition, is unwanted sound. What is pleasant to some ears may be extremely unpleasant to others, depending on a number of factors. The natural environment contains many sources of noise - wind, volcanoes, oceans, and animal sounds are all familiar intrusions accepted at various levels. Man-made noises - from machines, automobiles, trains, planes, explosives and firecrackers, etc. - are more contentious. Both kinds of noise affect sleep, hearing, communication, as well as mental and physical health.
Pollution is a noun derived from the verb pollute, meaning: to foul. It is now increasingly understood that pollution from noise is an important component of air pollution, which was previously understood as being limited to material pollution. Noise is an inescapable by-product of the industrial environment, which is increasing with advances in industrialization and urbanization. Even in non-industrial areas, noise from such activities as printing, auto-repair, grinding, affects those living in the immediate surroundings. Noise not only causes irritation or annoyance but also constricts the arteries, and increases the flow of adrenaline and forces the heart to work faster. Continuous noise causes an increase in the cholesterol level resulting in permanent constriction of blood vessels, making one prone to heart attacks and strokes. Health experts are of the opinion that excessive noise can also lead to neurosis and nervous breakdown.
Noise travels through air and hence it is measured in ambient air quality level. Noise is measured in decibels. Experts believe that continuous noise levels in excess of 90 decibels can cause loss of hearing and irreversible changes in nervous systems. The World Health Organization [WHO] has fixed 45 decibels as the safe noise level for a city. Metropolitan areas in India usually register an average more than 90 decibels; Mumbai is rated the third noisiest city in the world, with New Delhi following closely.
Waste and Water Pollution
When toxic substances enter lakes, streams, rivers, oceans, and other water bodies, they get dissolved or lie suspended in water or get deposited on the bed. This results in the pollution of water whereby the quality of the water deteriorates, affecting aquatic ecosystems. Pollutants can also seep down and affect the groundwater deposits.
Today, many people dump their garbage into streams, lakes, rivers, and seas, thus making water bodies the final resting place of cans, bottles, plastics, and other household products. The various substances that we use for keeping our houses clean add to water pollution as they contain harmful chemicals. In the past, people mostly used soaps made from animal and vegetable fat for all types of washing. But most of today’s cleaning products are synthetic detergents and come from the petrochemical industry. Most detergents and washing powders contain phosphates, which are used to soften the water among other things. These and other chemicals contained in washing powders affect the health of all forms of life in the water.
The effects of water pollution are not only devastating to people but also to animals, fish, and birds. Polluted water is unsuitable for drinking, recreation, agriculture, and industry. It diminishes the aesthetic quality of lakes and rivers. More seriously, contaminated water destroys aquatic life and reduces its reproductive ability. Eventually, it is a hazard to human health. Nobody can escape the effects of water pollution
Air Pollution
One of the formal definitions of air pollution is as follows – ‘The presence in the atmosphere of one or more contaminants in such quality and for such duration as is injurious, or tends to be injurious, to human health or welfare, animal or plant life.’ It is the contamination of air by the discharge of harmful substances. Air pollution can cause health problems and it can also damage the environment and property. It has caused thinning of the protective ozone layer of the atmosphere, which is leading to climate change.
Modernisation and progress have led to air getting more and more polluted over the years. Industries, vehicles, increase in the population, and urbanization are some of the major factors responsible for air pollution. The following industries are among those that emit a great deal of pollutants into the air: thermal power plants, cement, steel, refineries, petro chemicals, and mines.
Air pollution results from a variety of causes, not all of which are within human control. Dust storms in desert areas and smoke from forest fires and grass fires contribute to chemical and particulate pollution of the air. The source of pollution may be in one country but the impact of pollution may be felt elsewhere. The discovery of pesticides in Antarctica, where they have never been used, suggests the extent to which aerial transport can carry pollutants from one place to another.
Listed below are the major air pollutants and their sources.
Carbon monoxide (CO) is a colourless, odourless gas that is produced by the incomplete burning of carbon-based fuels including petrol, diesel, and wood. It is also produced from the combustion of natural and synthetic products such as cigarettes. It lowers the amount of oxygen that enters our blood . It can slow our reflexes and make us confused and sleepy.
Carbon dioxide (CO2) is the principle greenhouse gas emitted as a result of human activities such as the burning of coal, oil, and natural gases.
Chloroflorocarbons (CFC) are gases that are released mainly from air-conditioning systems and refrigeration. When released into the air, CFCs rise to the stratosphere, where they come in contact with few other gases, which leads to a reduction of the ozone layer that protects the earth from the harmful ultraviolet rays of the sun.
Lead is present in petrol, diesel, lead batteries, paints, hair dye products, etc. Lead affects children in particular. It can cause nervous system damage and digestive problems and, in some cases, cause cancer.
Ozone occur naturally in the upper layers of the atmosphere. This important gas shields the earth from the harmful ultraviolet rays of the sun. However, at the ground level, it is a pollutant with highly toxic effects. Vehicles and industries are the major source of ground-level ozone emissions. Ozone makes our eyes itch, burn, and water. It lowers our resistance to colds and pneumonia.
Nitrogen oxide (Nox) causes smog and acid rain. It is produced from burning fuels including petrol, diesel, and coal. Nitrogen oxides can make children susceptible to respiratory diseases in winters.
Suspended particulate matter (SPM) consists of solids in the air in the form of smoke, dust, and vapour that can remain suspended for extended periods and is also the main source of haze which reduces visibility. The finer of these particles, when breathed in can lodge in our lungs and cause lung damage and respiratory problems.
Sulphur dioxide (SO2) is a gas produced from burning coal, mainly in thermal power plants. Some industrial processes, such as production of paper and smelting of metals, produce sulphur dioxide. It is a major contributor to smog and acid rain. Sulfur dioxide can lead to lung diseases.
Chemical Pollution
In some parts of the world, the bodies of whales and dolphins washing ashore are so highly contaminated that they qualify as toxic waste and have to be specially disposed of. There are many different sources of chemical pollution, including:
- domestic sewage
- industrial discharges
- seepage from waste sites
- atmospheric fallout
- domestic run-off
- accidents and spills at sea
- operational discharges from oil rigs
- mining discharges and
- agricultural run-off.
However, the chemicals that are probably of most concern for everyone are the persistent pollutants: those substances that enter marine food chains and are eventually passed along the chain to the marine top predators in increasing amounts.Persistent pollutants include pesticides, such as DDT, and industrial chemicals, most famously the PCBs.
Hydro power he most common type of hydroelectric power plant uses a dam on a river to store water in a reservoir. Water released from the reservoir flows through a turbine, spinning it, which in turn activates a generator to produce electricity. But hydroelectric power doesn't necessarily require a large dam. Some hydroelectric power plants just use a small canal to channel the river water through a turbine. geothermal energy is the heat from the Earth. It's clean and sustainable. Resources of geothermal energy range from the shallow ground to hot water and hot rock found a few miles beneath the Earth's surface, and down even deeper to the extremely high temperatures of molten rock called magma. 
